A: 

In mathematics and physics, constants are often referred to by using the letter 'k'. This is probably where the convention comes from.

This is not an official code convention supported by Apple.

Duplicate of question 675816.

sebnow  2010-05-23 09:13:24
+1  A: 

This convention goes all the way back to the early days of Mac programming (1984, Pascal). k is the prefix for a constant and you will also see g as a prefix for globals.

Paul R  2010-05-23 09:28:32

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